- Able to take acetylsalicylic acid (ASA) 100 mg daily as prophylactic anticoagulation (patients intolerant to ASA may use low molecular weight heparin). Patients at high risk for thromboembolic events should receive low molecular heparin. Patients with history of thromboembolic event should pursue their ongoing anticoagulants (e.g. phenprocoumon, warfarin, heparin) or receive another adequate prophylaxis, at least LMWH).